Accelerating Copper Leaching from Sulfide Ores in Acid-Nitrate-Chloride Media Using Agglomeration and Curing as Pretreatment
, Junior Dupont 1, Osvaldo O. Herreros 2, Yecid P. Jimenez 1 and Cynthia M. Torres 3Round 1
Reviewer 1 Report
This is a good paper on the effect of pretreating a coarse chalcopyrite ore with chloride and nitrate salts. The results will be of general interest to the copper heap leaching community. There were only two things which I believe should be corrected:
Line 36: The authors state that pyro processing consumes more water and energy than hydro processing. Other than for fine grinding prior to flotation, this is probably not true, and many hydro processes also require fine grinding and concentration. I think the authors should either remove or justify this statement.
Line 51: Oxygen is not an ion. It is a molecular gas.
Other than that, and some minor English corrections, I believe that this paper is suitable for publication.
Author Response
Thank you for all suggestions and corrections.
About line 36, the sentence was delete.
About line 51, the word "ions" was changed by "agents".
Reviewer 2 Report
Line 39 to 41. Please write this phrase in another way, it has no sense.
Line 43 to 46. Explain more deeply the problem associated to ORP modification. In line 46 you refer to a layer which enhances the leaching kinetics, please, explain better.
Line 133 and line 139 you refer to Table 1 and Table 2, respectively, what is the variability of the data?. Are the results the average of two or three or more measurements?.
Table 3, line 145, why are these values studied?.
Line 173, please, more information about the design of these columns is desirable. Have they been used in another research?.
Table 5. The curing times were 20 and 30 days, why did you select these periods?.
Line 203-204. There are not comments about the use of optical microscope.
Line 250, please, write the idea in another way.
It would be interesting to study three different periods and three temperature values at least, with the aim to obtain a kinetic curve for the leaching process.
Figure 3 is wrong. The description does not match with the data in figure. C2 is not present.
Line 308-309, the phrase has no sense.
Author Response
Thank you for all suggestions and corrections.
About line 39 to 41, the sentence was improved.
About line 43 to 46, the ORP modification is explained by two chemical reactions that affect it. About porous layer, the explanation was improved.
About the information in Table 1 and Table 2, all data were corroborated by analytical technical. The authors have worked in leaching of ore using seawater for several years, so the results shown, are trustworthy. (Taboada, M.E., R. Quiroz, P.C. Hernández, A. Padilla, O.O. Herreros, and T.A. Graber. Copper ore leaching with pre-treatment. In: F. Valenzuela, et al., editors. Innovation, Development and Process Improvement. Hydroprocess ICMSE 2017; Cerda, C.P., M.E. Taboada, N.E. Jamett, Y. Ghorbani, and P.C. Hernández. Effect of Pretreatment on Leaching Primary Copper Sulfide in Acid-Chloride Media. Minerals. 2017;8(1); Hernández, P.C., M.E. Taboada, O.O. Herreros, T.A. Graber, and Y. Ghorbani. Leaching of Chalcopyrite in Acidified Nitrate Using Seawater-Based Media. Minerals. 2018;8(6); Castellón, C., M.E. Taboada, and P.C. Hernández. Lixiviación de concentrado de calcopirita por nitrato de sodio con agua de mar en un medio ácido. In: R. Monreal, L. Valenzuela, and F. Cendejas, editors. XXXI Convención Internacional de Minería Acapulco, México 2015. p. 227-234; Herreros, O., R. Quiroz, I. Campos, J. Rojas, and J. Viñals. Lixiviación de concentrados calcopiriticos con cloro. Innovación. 2001;13(2); Torres, C., M. Taboada, T. Graber, O. Herreros, Y. Ghorbani, and H. Watling. The effect of seawater based media on copper dissolution from low-grade copper ore. Minerals Engineering. 2015;71; Hernández, P., M. Taboada, O. Herreros, C. Torres, and Y. Ghorbani. Chalcopyrite dissolution using seawater-based acidic media in the presence of oxidants. Hydrometallurgy. 2015;157; Herreros, O., R. Quiroz, A. Restovic, and J. Viñals. Dissolution kinetics of metallic copper with CuSO4–NaCl–HCl. Hydrometallurgy. 2005;77(3–4))
About the variables chosen to be studied: the values of the nitrate addition were chosen due to the chemical reaction number 6 shown in Sokic et al. (2009). The values correspond to 1/4 and 1/2 of the stoichiometric value of the reaction. The rest of the nitrate will be provided by the leaching process. The chloride value of 2.1 kg/t corresponds to the presence in seawater according to the resting humidity and 20 kg/t, it is a value that is used in the copper industry (Spence, Escondida) and reported by Cerda et al. (2017). Temperature values are chosen because 25 ° C is similar to room temperature and 45 ° C is a moderate temperature and studied in several previous manuscripts. The resting time values are studied in previous works (Cerda et al. (2017), Taboada et al. (2017).)
The dimensions of the mini columns are commonly used in Chilean copper mining to laboratory tests. The same columns were used in Taboada, M.E., R. Quiroz, P.C. Hernández, A. Padilla, O.O. Herreros, and T.A. Graber. Copper ore leaching with pre-treatment. In: F. Valenzuela, et al., editors. Innovation, Development and Process Improvement. Hydroprocess ICMSE 2017. Moreover, in Velásquez-Yévenes, L. and V. Quezada-Reyes. Influence of seawater and discard brine on the dissolution of copper ore and copper concentrate. Hydrometallurgy. 2018;180:88-95; and, Velásquez-Yévenes, L., D. Torres, and N. Toro. Leaching of chalcopyrite ore agglomerated with high chloride concentration and high curing periods. Hydrometallurgy. 2018;181:215-220, the dimensions are similar.
About information in Table 5, 20 and 30 days of repose period were chosen of previous laboratory tests.
About line 203-204, a sentence was introduced about the use of optical microscope.
About line 250, the idea was modified.
We agree with study three different periods and three temperatures values to deeply in kinetic study. But this idea will be done in a future work.
About Figure 3, the C2 icons are over positions to C3 icons. We have modified the icons of C2 and C3 for a better distinction.
About line 308-309, the sentence was modified.
Round 2
Reviewer 2 Report
Indicate some references in the design of min columns.
It would be desirable to study more levels of variables.
Author Response
Thank your for the comments. About column design, we have added references in the text.
Now, we are working in the pretreatment effect on copper leaching adding new levels of variables. We hope publisch the results in a future manuscript. Thank you.
Best regards.
